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WASHINGTON (NEXSTAR) – The second FDA-approved coronavirus vaccine started arriving at medical facilities Monday.

Officials with the Trump administration’s Operation Warp Speed (OWS) plan to distribute 7.9 million Moderna and Pfizer shots this week, even during the holiday.

“If needed and if required and if asked for by the states, industry is ready to go with delivery on Christmas Day,” said Gen. Gustave Perna, the OWS chief operating officer.

Perna is in charge of vaccine distribution and reiterated his apology during a briefing Monday after states complained about receiving fewer vaccines than they were promised. He called it a miscommunication.

“Everybody is receiving fair and equitable distribution of the vaccine,” Perna said.

OWS officials said that will continue as a third vaccine hits the market early next year. Unlike the Pfizer and Moderna shots, the Johnson and Johnson vaccine will take just one dose. However, Dr. Moncef Slaoui, the chief advisor for OWS, said that doesn’t mean Johnson and Johnson’s is preferable to the others.

“All of these vaccines are important, and the doses are cumulative,” Slaoui said.

As more vaccine trials continue, Slaoui said so do studies of the shots in children. The FDA authorized the Pfizer vaccine for use in people 16 years of age and older, and Moderna’s shot for those 18 and up.

Slaoui stressed these 80 million children may be key to slowing the spread of the virus since they are usually asymptomatic.

“That’s why it’s really important that a large percentage of the population as a whole be vaccinated,” he said.

Slaoui said the shots are still on track to be widely available to all Americans by summer.

Following reports of a new mutation of the virus in the U.K., Slaoui said he expects the Pfizer and Moderna shots to be effective against the strain.

CVS also launched its partnership with the federal government Monday to vaccinate up to four million residents and staff at long-term care facilities across the country. The rollout begins with 12 states this week.